Last week I was chatting with a friend about a job interview he had recently been through after applying for a senior position at an international school in eastern Europe. For some employers, job interviews are subject to a kind of arms race, as they think up novel ways to unsettle candidates in order to “put them on the spot” and unearth their “deepest selves”. Judging by my friend’s account his new school seems to fall into that category. The process he described was long and wearisome, stretching out over three days and including any number of panel interviews, inbox challenges, real time simulations, ‘hard conversations’, psychometric tests, and so on and on.

One question he’d been asked particularly stuck with him, though. In itself, the question was deceptively simple, yet, he realised, genuinely revealing.

“You’ll be joining our school as a leader and shaper of young minds. In that role, share with us your greatest insight.”

If you pause to consider for a moment, that is a tough question to face without warning or preparation. You may have all kinds of insights that immediately spring to mind as candidates, but are they really that insightful? Are they really worth sharing? And have you really thought your way through all their consequences and ramifications? Will they stand up to the interviewing panel’s scrutiny? It can be rather terrifying to have to account for your thinking in this way.

I won’t tell you what he told them, though it appears it was good enough to get him the job; but I will tell you what I would have said, had I found myself in his shoes and “put on the spot” in the same fashion.

My insight would have been “where id was, there ego shall be.”

Which all seems a bit obscure. So I would have needed to explain.

The first thing I’d want to admit is that this is not actually my insight to begin with, it’s that of the famous German psychologist Sigmund Freud. And I would have explained that Freud offered this seven-word dictum as a guide to living a healthy mental life. And, I would have added that, in Freud’s opinion, it is very difficult to live a healthy and rewarding physical life unless you are mentally healthy, or, at least, reasonably so.

Freud believed that we had two aspects to our thinking - the conscious part, of which we are aware and which we can explain to ourselves and others; and the unconscious part, which is hidden from us and inaccessible, bubbling away like a cauldron coming to the boil in the deepest recesses of our mind. The conscious part is the ego, the unconscious part is the id.

Freud was convinced that the id’s influence is far more important than most people tend to realise. He claimed it is the home of all our desires and ambitions, our motivations and secret wishes, it is the wellspring of our self-story and lies behind most of what we say and do. And, more than anything, Freud insisted, it is irrational - it is incapable of or unwilling to abide by the rules of the real world. It is subject to magical thinking and wish fulfillment; it is self-seeking and self-absorbed, because it wants what it wants and it’s uninterested in what might make its desires impractical. Don’t get me wrong, the id is not all bad, by any means - we human beings, like all living creatures, have wants and needs, and, if we are to survive, must desire to fulfill them - but the id’s demands can become unsustainable.

And that is where the ego comes in. The ego is the brake on the id’s runaway engine of desire. It is the suppressor of the id’s limitless appetite.  Provided it is strong enough, the ego is the mind’s agent that can say “no” to the id’s never ending demands. The ego answers to what Freud calls the “reality principle”. It takes stock of actual circumstances in the real world and, on the basis of good information, makes a sensible decision about what is and is not possible. It denies the id its impossible demands.

So it is, said Freud, that if you want to be healthy and happy, “where id was, there ego shall be'' - or, in other words, you will substitute reason and reality for boundless, unsustainable desire. When necessary, you will put a curb on your enthusiasm.

That would be my insight, but I wouldn’t quite stop there. Because the truth is that Sigmund Freud has rather gone out of fashion, and it’s possible that the interview panel would think I was working with a discredited theory. Now, I happen to think they would be wrong in that, but my reality-testing ego wouldn’t want to take the chance.

So, I’d finish up by comparing Freud’s insight to the work of Daniel Kahneman, a Nobel Prize winner for his work in psychology, economics, and human behaviour.

Kahneman is the author of a fairly recent book, Thinking, Fast and Slow. As the title suggests, his research demonstrates that human thought can be characterised as falling into two types, which he calls System 1 and System 2.

System 1 thinking is fast. It is also unconscious, happens below our awareness, and is influenced heavily by past experiences, emotions and feelings, often unaccountable prejudices, and a great many shortfalls in cognition which are simply a product of our evolutionary past. System 1 thinking goes on all the time, completely unbidden, and, for the most part, calls the shots as we live our daily lives.

System 2 thinking, on the other hand, is slow. It is conscious and it is hard work. It requires us to pause, to get a grip on our thoughts, to place things in proper relation to one another, and to test our hypotheses and theories against reality. It requires us to admit that we might be wrong. No wonder, notes Kahneman, that we don’t much like doing it and avoid it as much as we can. However, it is only through System 2 thinking, he reminds us, that we can ensure that the promptings of System 1 are fit for purpose and well advised.

You will spot, I am sure, the resemblances and overlaps between the id and System 1, on the one hand, and the ego and System 2, on the other.

Both Freud and Kahneman offer a similar insight - if you want to live a happy, fulfilled, rewarding, sustainable life, you must be prepared to pause a moment, put a brake on your desires, subject your thinking to scrutiny, question your assumptions and motivations, and be prepared to change your mind. It’s not easy, as they freely admit; it requires strength and energy, but, without the effort to test reality and bring System 2 thinking online, you risk endless disappointment and frustration. Make that effort, slow down your racing mind, and “where id was, there ego shall be.”

That’s my insight. Or Freud’s insight. Kahneman’s insight. Think about it. You’re welcome.